A nightclub fire in North Macedonia claimed hundreds of casualties early Sunday.

The blaze at Club Pulse in the town of Kocani is believed to have begun when a pyrotechnics display set the roof afire during a concert around 2:30 a.m. local time. Authorities took one person into custody while investigating the incident, though it was not clear why.

At least 59 people died and 18 others were in critical condition. Authorities said 155 clubgoers were injured.

Among the dead is a 21-year-old man named Tomce, according to his father, Dragi Stojanov.